It's the old Algebra 1 mixture problem. You're adding a high % solution to the overall mixture, increasing the % of the entire mixture.
I think the ACC and Big12 are currently on about the same $/team for TV money. But since Clemson & FSU are the big brands, they would certainly be worth more than the average, so would bring the avg UP for the Big12. Esp because the range from top to bottom in the ACC is wider than in the Big12.
Swagging some numbers... I get this adds something like $5M per team overall to the Big12. And you stick a knife in the ACC as well. So that's great. But why would FSU & Clemson jump for $5M additional, when they want $20-30M additional?
Unequal revenue sharing? I don't think the Big12 members would accept it, knowing what it has done in the past. Maybe that's where PE comes in, they put up a bunch of money to buy FSU & Clemson, and take a chunk of the upper on the next TV contract. As long as you aren't giving up too much future money (or making it mostly a bet on the increase for the PE) it could make sense. Lots of ifs and buts to be sure...